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1.
Lancet Haematol ; 11(5): e368-e382, 2024 May.
Article in English | MEDLINE | ID: mdl-38697731

ABSTRACT

Diamond-Blackfan anaemia (DBA), first described over 80 years ago, is a congenital disorder of erythropoiesis with a predilection for birth defects and cancer. Despite scientific advances, this chronic, debilitating, and life-limiting disorder continues to cause a substantial physical, psychological, and financial toll on patients and their families. The highly complex medical needs of affected patients require specialised expertise and multidisciplinary care. However, gaps remain in effectively bridging scientific discoveries to clinical practice and disseminating the latest knowledge and best practices to providers. Following the publication of the first international consensus in 2008, advances in our understanding of the genetics, natural history, and clinical management of DBA have strongly supported the need for new consensus recommendations. In 2014 in Freiburg, Germany, a panel of 53 experts including clinicians, diagnosticians, and researchers from 27 countries convened. With support from patient advocates, the panel met repeatedly over subsequent years, engaging in ongoing discussions. These meetings led to the development of new consensus recommendations in 2024, replacing the previous guidelines. To account for the diverse phenotypes including presentation without anaemia, the panel agreed to adopt the term DBA syndrome. We propose new simplified diagnostic criteria, describe the genetics of DBA syndrome and its phenocopies, and introduce major changes in therapeutic standards. These changes include lowering the prednisone maintenance dose to maximum 0·3 mg/kg per day, raising the pre-transfusion haemoglobin to 9-10 g/dL independent of age, recommending early aggressive chelation, broadening indications for haematopoietic stem-cell transplantation, and recommending systematic clinical surveillance including early colorectal cancer screening. In summary, the current practice guidelines standardise the diagnostics, treatment, and long-term surveillance of patients with DBA syndrome of all ages worldwide.


Subject(s)
Anemia, Diamond-Blackfan , Consensus , Humans , Anemia, Diamond-Blackfan/diagnosis , Anemia, Diamond-Blackfan/therapy , Anemia, Diamond-Blackfan/genetics , Disease Management , Hematopoietic Stem Cell Transplantation
2.
Clin Appl Thromb Hemost ; 29: 10760296231182410, 2023.
Article in English | MEDLINE | ID: mdl-37525882

ABSTRACT

Establishing a national screening program for hemophilia patients is highly encouraged by the World Health Organization and the World Federation of Hemophilia. Hence, this study aimed to analyze the variant spectrum of F8 and F9 genes in Arab hemophilia patients. Molecular genetic and sequencing studies were performed on a cohort of 135 Saudi hemophilia patients. Out of all screened hemophilia patients (97 hemophilia A and 39 hemophilia B), 15 (11.1%) were positive for inversion 22 and 4 (3%) for inversion 1. Out of a total of 32 (23.7%) substitution/deletion mutations, 2 novel variants were identified: a novel splice acceptor site missense mutation (c.5816-2A > G) causing a pathogenic variant of the F8 gene and another splicing site point mutation in intron/exon 23 (g.164496G > A). The frequent F8 variants were (c.409A > C, p.T137P) in exon 4, (c.760A > G) in exon 6, and (c.1835G > C, p.R612P) in exon 12, while the frequent F9 variants were (c.580A > G) in exon 6 and (c.880C > T) in exon 8. These study data will enrich the spectrum of the genetic databases in the Arab population that could be applied in the future for national genetic counseling.


Subject(s)
Hemophilia A , Hemophilia B , Humans , Hemophilia A/diagnosis , Hemophilia A/genetics , Factor VIII/genetics , Hemophilia B/genetics , Mutation, Missense , Genotype , Mutation
3.
J Taibah Univ Med Sci ; 18(2): 413-419, 2023 Apr.
Article in English | MEDLINE | ID: mdl-37102076

ABSTRACT

Objectives: This study was aimed at assessing the clinical presentations and laboratory findings among patients diagnosed with vWD at a Saudi tertiary care unit. Methods: This retrospective study included 189 patients with vWD who were followed up in our unit over 4 years. Clinical and laboratory data were collected and analyzed in SPSS. Results: The median age of the study cohort was 30 years (range 11 months-56 years). The cohort had a female preponderance, with 32.30% males and 66.70% females. Bleeding from different sites was observed, mostly from the joints and muscles (23.90%), followed by the mucus membranes (14.60%), genitourinary areas (7.70%), ecchymoses (2.80%), and gastrointestinal areas (2.80%). A total of 48% of participants presented with more than one type of bleeding. A total of 105 (58.01%) participants had type 1; 29 (16.02%) had type 2; and 47 (25.96%) had type 3 vWD. Blood tests indicated the following mean value: hemoglobin, 116 ± 25.60 gm/L; ferritin, 75.80 ± 166.80 µg/L (median 28.5); vWAg, 0.40 ± 0.27IU/ml; and vWD:RCo, 0.32 ± 0.20IU/dL. The partial thromboplastin time was prolonged in 49.20% and normal in 50.80% of participants. Platelet function analysis values were prolonged in 92.90% and normal in 7.10% of participants. Comparative analysis of the O-type and non-O blood type showed that blood type O was significantly correlated with factor VIII (p-value = 0.013), vWF:RCo (p-value = 0.004), and vWF:Ag (p-value = 0.019). Conclusion: Joint and muscle bleeds were the most common clinical presentations in our cohort. Although type 1 vWD was most prevalent in our cohort, we observed a comparatively higher prevalence of type 3, possibly because of ethnic differences or referral bias. We found a significant difference between O and non-O blood type regarding FVIII and vWF:Ag, and observed a more pronounced difference for vWD activity measuresd by vWF:RCo with blood type O being the systematic factor.

4.
J Blood Med ; 12: 819-826, 2021.
Article in English | MEDLINE | ID: mdl-34512062

ABSTRACT

BACKGROUND: COVID-19 wreaked havoc on the healthcare system, with more than 36 million cases reported globally. Although the pediatric population makes up a lesser proportion of total COVID-19 patients than adults, the clinical status, age and comorbidities warrant identifying possible prognostic factors associated with disease severity in this group. The current study aimed to explore the incidence of thrombosis, overall outcome, and different hematological and coagulation markers in children with COVID-19. METHODS: This is a single-center prospective study of 43 patients (age < 14 years) with confirmed COVID-19 diagnosis recruited from April to August 2020. Data for clinical presentation were collected and analyzed. The samples were tested for different hematological and coagulation markers. RESULTS: Twenty-nine (67.4%) were symptomatic at presentation, with fever being the most common symptom (n = 23, 53.5%), followed by respiratory (n = 5, 11.6%) and gastrointestinal symptoms (n = 3, 7%). Co-morbid conditions were recorded in 26 (60.5%) patients, with malignancy being the commonest (n = 9, 20.9%). In this cohort of patients with age <14 years, hypertension, respiratory symptoms and ABO group-A were significantly associated with pediatric intensive care unit (PICU) admission during the course of treatment. Patients with elevated FVIII and fibrinogen levels at presentation were more likely to have an extended length of hospital stay (LOS) (P-value =0.036 and 0.032 respectively). No thrombotic event was observed in our cohort. D-dimer values were higher (above 0.5 µg/mL) in 24 (55.8%) patients at admission. We found an association between high D-dimer and PICU admission and LOS. CONCLUSION: Although we did not observe thrombosis in our cohort, serial measurements of D-dimer and elevated FVIII bear a prognostic value in predicting the need for critical care in children with COVID-19. Further studies with larger sample size can aid in the establishment of prognostic factors for the pediatric COVID-19 population.

5.
Am J Blood Res ; 11(3): 317-324, 2021.
Article in English | MEDLINE | ID: mdl-34322296

ABSTRACT

BACKGROUND: Procoagulant profile of 2019-nCoV/SARS-CoV-2 has been well documented over the last year. Perturbance in coagulating factors has also been reported in Covid-19 patients, including increased d-dimers and reports of lupus anticoagulant (LA). METHODS: The current study aimed to identify the incidence of positivity of lupus anticoagulant in Covid-19 patients and analyze the association between LA and D-dimer in predicting thrombosis and mortality in one-hundred and five hospitalized adult (age >14 years) patients and forty-three hospitalized pediatric (age <14 years) patients with a confirmed diagnosis of Covid-19 between June 2020 and September 2020. RESULTS: Twenty-one (20%) adult patients were tested positive for PTT LA, of which nine (8.6%) turned out to be confirmed positive for LA through StaClot and DRVVT Ratio tests. Six (14%) pediatric patients were positive for PTT LA, and only one (2.3%) had positive StaClot. Median D-dimer at admission was positively correlated with age and CRP among adult patients and was significantly higher in expired cases (P=0.001). No association between any of the coagulation tests and thrombosis or mortality was observed in the pediatric cohort. CONCLUSION: We report an increased incidence of LA in Covid-19 patients, yet we didn't find any association between thrombotic events or mortality, probably due to the small sample size.

6.
J Hematol ; 10(3): 106-113, 2021 Jun.
Article in English | MEDLINE | ID: mdl-34267847

ABSTRACT

BACKGROUND: Essential thrombocythemia (ET) is one of the "classic" Philadelphia chromosome negative (Ph-) myeloproliferative neoplasms characterized by sustained thrombocytosis, increased megakaryopoiesis and high risk of vascular complications. ET is very rare in childhood. The annual incidence is approximately 1 per 10,000,000 in children less than 14 years, and about 60 times lower than adults. The genetic landscape and clonal features in childhood ET has not been well defined. There is no evidence-based guidance on the diagnosis of childhood ET. METHODS: Medical records of 28 pediatric patients (age ≤ 14 years at diagnosis) with ET were reviewed and evaluated to characterize the different mutation profiles and to evaluate the treatment modalities used and the potential long-term outcome. RESULTS: More than half of the patients were found to have positive history of parental consanguinity (57.1%) whereas positive family history was documented for more than a quarter of our patients (28.6%). Janus kinase 2 gene (JAK2) V617F mutation was positive in two of 26 patients (7.7%). Myeloproliferative leukemia virus oncogene (MPL) exon 10 and calreticulin (CALR) mutations were tested in eight patients, which were negative for all of them. Treatment included low-dose aspirin (LDA) in seven patients (50%), combination of LDA with hydroxyurea in three patients (21.4%), hydroxyurea in two patients (14.3%), combination of platelets apheresis with LDA and anagrelide in one patient each (7.1%). During the treatment, two patients experienced stroke (7.1%), one patient developed Budd-Chiari syndrome (3.6%) and one patient developed azoospermia (3.6%). CONCLUSIONS: The incidence of ET in children is extremely low in Saudi Arabia. Most of the children with ET were asymptomatic, and thrombocytosis was often discovered incidentally. JAK2 V617F mutation has no known impact on the prognosis or on the outcome of the disease in the pediatric age group that is in contrast to the adult ET. Children less than 1 year are at high risk for complications particularly during acute precipitating infectious episode. The potential complications and clinical course of pediatric ET are unpredictable.

7.
Adv Hematol ; 2020: 8768074, 2020.
Article in English | MEDLINE | ID: mdl-32963537

ABSTRACT

BACKGROUND: The one-stage assay is the most common method to measure factor VIII activity (FVIII : C) in hemophilia A patients. The chromogenic assay is another two-stage test involving purified coagulation factors followed by factor Xa-specific chromogenic substrate. AIM: This study aimed to assess the discrepancy and correlation between the chromogenic and one-stage assays in measuring FVIII : C levels in hemophilia patients receiving Extended Half-Life Elocta® as a recombinant extended half-life coagulation factor. METHODS: We performed a study comparing the measurements of FVIII : C levels by the chromogenic versus the one-stage assays at different drug levels. Data of FVIII : C levels, dosage, and the time interval from administration to measurement were retrieved from the hospital records. The correlation, mean differences, and discrepancy between the two assays were calculated. The linear regression analysis was used to predict the time interval till reaching 1% FVIII : C. RESULTS: Fourteen patients with 56 samples were included in the study. Of them, 13 patients were receiving Elocta® as a prophylactic, while one was receiving Elocta® on demand. One-third of these samples showed a discrepancy between the chromogenic and one-stage assays. The two assays were well correlated. Mean differences were significant at the individual and the time interval level. The time since the last Elocta® injection could significantly predict FVIII : C levels (ß = 0.366, P < 0.001). CONCLUSION: Our findings suggested a significant difference between both methods; the FVIII : C levels measured by the one-stage assay were less than those estimated by the chromogenic assay. However, the measurements of FVIII levels by the two assays were well correlated but discrepant in one-third of the samples. The levels of FVIII : C reach 1% after 5.4 days since the last Elocta® administration.

8.
Blood Coagul Fibrinolysis ; 30(5): 224-232, 2019 07.
Article in English | MEDLINE | ID: mdl-31268865

ABSTRACT

Coagulation factor V plays a significant role in the blood coagulation cascade as part of the prothrombinase complex. Factor V deficiency (FVD) is a rare autosomal recessive bleeding disorder with a variable phenotypic expression which varies from being asymptomatic-to-severe bleeding episodes. The aim of this study was to perform molecular and clinical characterization of FVD in patients originating from Saudi Arabia. Eleven patients (two males and nine females) with confirmed FVD were recruited in the study with ages ranging between 5 and 53 years. A next-generation sequencing-based hematology panel encompassing 393 known genes was used. A total of six sequence variations in F5 gene were identified, including four missense mutations (p.Pro189Leu, p.Trp2004Arg, p.Met2148Thr, p. Arg2202Cys), a deletion (p.Arg872Lysfs*12) and a splicing variant (c.1118+5G>T). Four variants were identified for the first time in this study. Three patients were homozygous for their respective mutations and seven patients were heterozygous. We were not able to identify a pathogenic variant in one patient of the cohort. In-silico and three-dimensional structural analyses were performed to predict the possible impact and functional consequences of the identified variants. To our knowledge, this is the first study addressing factor V mutations in patients with Arab ancestry. Results have helped in providing a definitive diagnosis to the patients and carrier detection in extended family members. Overall, the hematology panel assay was an efficient platform, demonstrating a formidable approach for the molecular diagnosis of other suspected bleeding disorders.


Subject(s)
Factor V Deficiency/genetics , Factor V/genetics , Adolescent , Adult , Base Sequence , Child , Child, Preschool , Factor V Deficiency/epidemiology , Female , Humans , Male , Middle Aged , Models, Molecular , Mutation, Missense , Protein Conformation , Protein Isoforms/chemistry , Protein Isoforms/genetics , Saudi Arabia/epidemiology , Sequence Deletion , Young Adult
9.
NPJ Genom Med ; 4: 4, 2019.
Article in English | MEDLINE | ID: mdl-30792900

ABSTRACT

Glanzmann thrombasthenia (GT) is a rare autosomal recessive bleeding disorder. Around 490 mutations in ITGA2B and ITGB3 genes were reported. We aimed to use targeted next-generation sequencing (NGS) to identify variants in patients with GT. We screened 72 individuals (including unaffected family members) using a panel of 393 genes (SHGP heme panel). Validation was done by Sanger sequencing and pathogenicity was predicted using multiple tools. In 83.5% of our cohort, 17 mutations were identified in ITGA2B and ITGB3 (including 6 that were not previously reported). In addition to variants in the two known genes, we found variants in ITGA2, VWF and F8. The SHGP heme panel can be used as a high-throughput molecular diagnostic assay to screen for mutations and variants in GT cases and carriers. Our findings expand the molecular landscape of GT and emphasize the robustness and usefulness of this panel.

10.
Adv Hematol ; 2018: 1858241, 2018.
Article in English | MEDLINE | ID: mdl-29853900

ABSTRACT

BACKGROUND: Bleeding disorders vary in prevalence. While some are rare, some can be common in both sexes. Most bleeding disorders manifest as chronic bleeding tendencies or as an increase in bleeding during surgical procedures or trauma. The consequences of bleeding can be as simple as iron deficiency or catastrophic, resulting in severe morbidity and mortality. Bleeding disorders typically affect both sexes except hemophilia A and B, which mainly affects males. METHOD: We conducted a questionnaire-based survey among adolescents and young adults (1901 [49%] boys, 1980 [51%] girls) in Riyadh city regarding bleeding symptoms. Of these, 1849 (47.6%) responded "Yes/Positive" for at least one question about the bleeding symptoms. RESULTS: The most common bleeding symptom was epistaxis (19.7% of the sample population) detected in Phase I of the study. A tandem survey was conducted among 525 adolescents who had responded "Yes/Positive" to any one of the questions inquiring about bleeding symptoms. CONCLUSION: In this study, we report for the first time the prevalence of bleeding symptoms in a representative sample of Saudi adolescents and young adults.

11.
Medicine (Baltimore) ; 96(2): e5456, 2017 Jan.
Article in English | MEDLINE | ID: mdl-28079788

ABSTRACT

Hemophilia A and B are X-linked diseases that predominantly affect male patients. Patients can develop coagulation factor inhibitors, which exponentially increases the treatment cost. However, the prevalence of factor VIII and IX inhibitors in Saudi Arabia is unclear.This study aimed to determine the Saudi prevalence of factor VIII and IX inhibitors.This 4-year, 7-center, cross-sectional study evaluated the Saudi prevalences of hemophilia A and B. We collected the patients' clinical data, evaluated their disease, and tested for factor inhibitors.We included 202 patients with hemophilia (median age at diagnosis: 0.13 years, range: birth-34.8 years). The patients included 198 male patients (98%), 148 patients with hemophilia A (73.3%), and 54 patients with hemophilia B (26.7%). The patients exhibited severe factor VIII activity (<1%; 121 patients; 5.2%), moderate activity (1-5%; 7 patients; 4.9%), and mild activity (14 patients; 9.9%). Among the patients with care-related data, most patients were treated for episodic bleeding (76.8%) or received prophylaxis (22.6%); 1 patient received both treatments. Among the patients with source-related data, the factor replacements were derived from plasma (48.4%), recombinant concentrates (22.9%), both sources (14.6%), or fresh frozen plasma (14.1%). Factor VIII inhibitors were observed in 43 (29.3%) of the 147 patients, and only 1 of the 54 patients developed factor IX inhibitors. Most patients who developed inhibitors had severe hemophilia (40/44; 90.9%), and inhibitors were also common among patients who received recombinant products (14/43; 32.6%).The Saudi prevalence of factor inhibitors was similar to those among other ethnic populations.


Subject(s)
Drug Resistance , Factor IX/antagonists & inhibitors , Factor VIII/antagonists & inhibitors , Hemophilia A/drug therapy , Hemophilia B/drug therapy , Adolescent , Adult , Child , Child, Preschool , Cross-Sectional Studies , Female , Hemophilia A/blood , Hemophilia A/complications , Hemophilia B/blood , Hemophilia B/complications , Hepatitis C/blood , Hepatitis C/complications , Humans , Infant , Infant, Newborn , Joint Diseases/etiology , Male , Saudi Arabia , Young Adult
12.
Asian Cardiovasc Thorac Ann ; 20(2): 153-9, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22499962

ABSTRACT

Current dosing guidelines for unfractionated heparin therapy in pediatric patients are based on recommendations of only one study that evaluated a weight-based dosing nomogram. To test the hypothesis that adhering to a strict weight-based nomogram yields better therapeutic results in pediatric patients, we prospectively monitored 25 consecutive pediatric patients who received unfractionated heparin based on the nomogram, and compared them to control patients whose treatment did not follow the standard nomogram. The mean time needed to achieve the target activated partial thromboplastin time was significantly shorter in the study group than the control group (18.32 ± 9.98 vs. 43.8 ± 30 h). A higher proportion of the study group reached the target activated partial thromboplastin time at 12, 24, and 36 h, compared to controls: 44% vs. 6%, 72% vs. 28%, 100% vs. 58%, respectively. Within the study group, patients under 1 year of age needed more time to achieve the target activated partial thromboplastin time than those over 1-year old. The performance of the standard dosing nomogram was excellent with regard to early anticoagulation target achievement, without increasing the risk of bleeding. Further studies are warranted to refine this nomogram for pediatric patients who are less than 1-year old.


Subject(s)
Anticoagulants/administration & dosage , Drug Monitoring/methods , Heparin/administration & dosage , Thromboembolism/prevention & control , Anticoagulants/therapeutic use , Body Weight , Child, Preschool , Dose-Response Relationship, Drug , Female , Follow-Up Studies , Heparin/therapeutic use , Humans , Infant , Infusions, Intravenous , Male , Partial Thromboplastin Time , Prospective Studies , Thromboembolism/blood
13.
Blood Coagul Fibrinolysis ; 20(6): 415-8, 2009 Sep.
Article in English | MEDLINE | ID: mdl-19448530

ABSTRACT

Different types of mutations have been reported in patients with hemophilia A. Although about half of all severe factor VIII deficiencies are caused by gene rearrangements (inversions) involving intron 22 in F8, other mutations such as point mutation, large deletions and insertions had been reported. We report the result of the first molecular testing for or F8 mutations from Saudi Arabia. A cohort of 22 men with hemophilia A was studied for F8 mutations. All patients were tested for factor VIII coagulant activity and inhibitors. Peripheral blood samples were used for DNA extraction followed by PCR detection of intron 22 inversion and all samples tested negative were screened for other F8 mutations. The patient's age ranged between 4 and 37 years. All patients except two siblings had severe hemophilia A. Only two patients out of 22 developed inhibitors with no obvious relation to the genotype. F8 Intron 22 inversion was detected in 10 patients (50%) of severe cases. Additionally, five point mutations and one deletion/insertion involving different exons were detected. All identified mutations were associated with severe phenotype except for one, which was associated with mild phenotype of hemophilia. This is the first report of molecular genotype of hemophilia A in the Saudi population and one of the few for Arab population. We had confirmed the incidence of Inversion 22 in severe hemophilia. We are reporting two novel mutations in F8, which can be used for carrier detection and prenatal genetic diagnosis (PGD).


Subject(s)
Arabs/genetics , Factor XII/genetics , Hemophilia A/genetics , Mutagenesis, Insertional , Mutation, Missense , Sequence Deletion , Adolescent , Adult , Autoantibodies/immunology , Codon, Nonsense , DNA Mutational Analysis , Factor XII/immunology , Frameshift Mutation , Genotype , Hemophilia A/ethnology , Humans , Introns/genetics , Isoantibodies/immunology , Male , Phenotype , Saudi Arabia/epidemiology , Young Adult
14.
Ann Saudi Med ; 28(4): 251-9, 2008.
Article in English | MEDLINE | ID: mdl-18596394

ABSTRACT

BACKGROUND AND OBJECTIVE: Because of the need for more comprehensive information on the least toxic and most effective forms of therapy for children with acute lymphoblastic leukemia (ALL), we reviewed our experience in the treatment of children with ALL at King Faisal Specialist Hospital and Research Centre (KFSH&RC) and King Fahad National Center for Children's Cancer and Research (KFNCCC&R) over a period of 18 years with a focus on patient characteristics and outcome. METHODS: During the period of 1981 to 1998, records of children with ALL were retrospectively reviewed with respect to clinical presentation, laboratory findings, risk factors, stratification, therapy and outcome. The protocols used in treatment included 4 local protocols (KFSH 81, 84, 87 and 90), and subsequently, Children's Cancer Group (CCG) protocols, and these were grouped as Era 1 (1981-1992) and Era 2 (1993-1998). RESULTS: Of 509 children with ALL treated during this period, 316 were treated using local protocols and 193 using CCG protocols. Drugs used in Era 1 included a 4-drug induction using etoposid (VP-16) instead of L-asparaginase. Consolidation was based on high dose methotrexate (MTX) 1 g/m(2) and maintenance was based on oral mercaptopurine (6-MP) and MTX with periodic pulses using intravenous teniposide (VM-26), Ara-C, L-asparaginase, adriamycin, prednisone, VP-16 and cyclophosphamide. International protocols were introduced in Era 2, which was also marked by intensification of early treatment, a wider selection of cytoreductive agents, and the alternating use of non-cross-resistant pairs of drugs during the post-remission period. The end-of-induction remission rate improved from 90% in Era 1 to 95% in Era 2, which was of borderline statistical significance (P=.049). The 5-year event-free survival (EFS) improved from 30.6% in Era 1 to 64.2% in Era 2 (P<.001). Improvement in outcome was achieved without any significant increase in morbidity or mortality, due to improvement in both systemic therapy and supportive care. The most important independent prognostic factors were intensity of therapy, poor risk category assignment and CNS disease at diagnosis. CONCLUSION: Outcome in children with ALL has improved because of intensification of treatment protocols and better supportive care.


Subject(s)
Precursor Cell Lymphoblastic Leukemia-Lymphoma/therapy , Child , Child, Preschool , Clinical Trials as Topic , Combined Modality Therapy , Female , Humans , Infant , Male , Precursor Cell Lymphoblastic Leukemia-Lymphoma/mortality , Retrospective Studies , Risk Factors , Saudi Arabia , Survival Analysis , Treatment Outcome
15.
Saudi Med J ; 26(4): 674-7, 2005 Apr.
Article in English | MEDLINE | ID: mdl-15900384

ABSTRACT

The present report describes the clinical, hematological and molecular characteristics in a family with unique interaction between 3 different mutations discovered during routine workup for bone marrow transplantation. In this report, complete hematological and molecular studies were performed for a large Saudi family. The family consisted of parents and 9 children, which revealed that the father is compound heterozygous for hemoglobin Hb D Punjab/beta-thalassemia, the mother is a carrier for beta-thalassemia and 3 of their children are transfusion dependent beta-thalassemia. Two of the children are compound heterozygous for Hb D Punjab/beta-thalassemia like the father but with different genotype. The other 2 children have Hb D Punjab traits while 2 other children have beta-thalassemia traits. Although, compound heterozygous for Hb D/beta-thalassemia has been well described in the literature, our report emphasizes the importance of careful analysis of the electrophoresis results and the usefulness of molecular studies in premarital screening and other screening hemoglobinopathy programs.


Subject(s)
Hemoglobins, Abnormal/genetics , beta-Thalassemia/genetics , Adolescent , Female , Heterozygote , Humans , Male , Mutation , Pedigree
16.
Thromb Haemost ; 91(1): 16-27, 2004 Jan.
Article in English | MEDLINE | ID: mdl-14691564

ABSTRACT

The contribution of the factor Va C1 domain (fVa-C1) to assembly of the prothrombinase complex has not been previously investigated. The homologous fVa-C2 domain contains a binding site for phosphatidylserine (PS) that includes the indole moieties of Trp(2063)/Trp(2064) at the apex of spike-1. In order to investigate the structure and function of fVa-C1 a molecular model was constructed based on the structure of fVa-C2. The aromatic and hydrophobic side chains of Tyr (1956) /Leu (1957) in fVa-C1 are located at the predicted apex of spike-3. Exposed charged and hydrophobic residues in fVa-C1 were changed to alanine in clusters of 1-3 mutations per construct. The resultant 20 mutants were expressed in COS cells and screened for binding to immobilized PS and prothrombinase activity on phospholipid vesicles containing either 25% or 5% PS. Two mutants, (Y1956,L1957)A, and (R2023,R2027)A showed both decreased binding to immobilized PS and a selective decrease in prothrombinase activity on membranes containing 5% PS. The interaction of purified (Y1956,L1957)A with phospholipid vesicles was studied using fluorescence resonance energy transfer and prothrombinase assays. The affinity of (Y1956,L1957)A binding to 25% PS membranes was reduced 12-fold compared to rHFVa. Prothrombin activation in the presence of (Y1956,L1957)A was markedly impaired on phos-pholipid vesicles containing 10% or less PS. We conclude that solvent exposed hydrophobic and aromatic amino acids in both fVa-C1 and fVa-C2 contribute to the interaction of factor V with PS membranes.


Subject(s)
Cell Membrane/metabolism , Factor V/chemistry , Alanine/chemistry , Amino Acid Sequence , Animals , COS Cells , Culture Media, Conditioned/pharmacology , DNA, Complementary/metabolism , Dose-Response Relationship, Drug , Enzyme-Linked Immunosorbent Assay , Fluorescence Resonance Energy Transfer , Humans , Kinetics , Mice , Models, Molecular , Molecular Sequence Data , Mutagenesis, Site-Directed , Mutation , Phosphatidylserines/chemistry , Phospholipids/chemistry , Protein Binding , Protein Structure, Tertiary , Thromboplastin/chemistry , Thromboplastin/metabolism
17.
Cancer ; 97(11): 2898-903, 2003 Jun 01.
Article in English | MEDLINE | ID: mdl-12767105

ABSTRACT

BACKGROUND: The goals of the current study were to examine the incidence and severity of toxicity resulting from dexamethasone and prednisone during induction therapy for children with precursor B-cell acute lymphoblastic leukemia (ALL) and to determine whether the addition of daunomycin affected toxicity. METHODS: Medical records of patients with precursor B-cell ALL from January 1996 through June 2000 were reviewed retrospectively for toxicity during the 4-week induction phase and the 2 weeks after the induction phase. RESULTS: One hundred seventy-six patients age < 14 years were diagnosed with precursor B-cell ALL from January 1996 through June 2000. Of the 156 evaluable patients, 106 were treated with prednisone and 50 with dexamethasone. Fifty-two patients received steroids, L-asparaginase, and vincristine, whereas 104 high-risk patients received daunomycin in addition to these 3 agents. The incidence of gastritis was significantly higher among patients receiving dexamethasone (P = 0.01); incidence rates of hyperglycemia, hypertension, and myopathy were similar for all treatment groups. Dexamethasone led to more weight gain than did prednisone (+11.9% vs. +5.4%; P = 0.002). Serious infections were observed in 27 (25.5%) and 18 (36%) patients receiving prednisone and dexamethasone, respectively (P < or = 0.2). Five patients, four of whom received prednisone and one of whom received dexamethasone, died of infection. The addition of daunomycin to treatment regimens increased overall toxicity (P < 0.01). When daunomycin was included in treatment regimens, toxicity was greater among patients receiving dexamethasone; in contrast, when daunomycin was not included, toxicity was equal for both treatment groups. Regardless of daunomycin use, there was no difference in the incidence of serious infection between the two groups. ALL treatment was not compromised by steroid-related toxicity in either group. CONCLUSIONS: The addition of daunomycin led to a much larger increase in dexamethasone-related toxicity compared with the increase in prednisone-related toxicity. Although the use of daunomycin enhanced dexamethasone-related toxicity, this enhancement did not result in a higher mortality rate or the alteration of planned ALL therapy.


Subject(s)
Antibiotics, Antineoplastic/adverse effects , Antineoplastic Agents, Hormonal/adverse effects , Burkitt Lymphoma/drug therapy , Daunorubicin/adverse effects , Dexamethasone/adverse effects , Adolescent , Asparaginase/administration & dosage , Drug Therapy, Combination , Humans , Prednisone/administration & dosage , Prednisone/adverse effects , Retrospective Studies , Vincristine/administration & dosage
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